Bus control circuit, semiconductor integrated circuit, circuit board, information processing device and bus control method

ABSTRACT

A bus control circuit for transferring an exclusive command between first and second bus specifications by mutually converting a first exclusive command of the first bus specification which deals with an exclusive access, and a second exclusive command of the second bus specification which doesn&#39;t deal with the exclusive access, includes an exclusive command conversion circuit receiving the first exclusive command, converting and outputting the second exclusive command, when converting from the first to second exclusive commands; an exclusive command generation circuit receiving the second exclusive command and generating the first exclusive command, when converting from the second to first exclusive commands; an exclusive response issuing circuit issuing exclusive response information for the second exclusive command, when converting from the second to first exclusive commands; and an exclusive response receiving circuit receiving exclusive response information for the second exclusive command, when converting from the first to second exclusive commands.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application and is based upon PCT/JP2017/017601, filed on May 9, 2017, which claims the benefit of priority of the prior Japanese Patent Application No. 2016-169971, filed on Aug. 31, 2016, the entire contents of which are incorporated herein by reference.

FIELD

The present invention relates to a bus control circuit, a semiconductor integrated circuit, a circuit board, an information processing device and a bus control method.

BACKGROUND

Recently, in information processing systems such as a server or the like, for example, a plurality of semiconductor integrated circuits or circuit boards applying to different bus specifications have been used. In the semiconductor integrated circuits applying to the different bus specifications, for example, there are sometimes difficult to reloaded information of a first bus specification to information of a second bus specification which is different from the first bus specification.

Concretely, in an SoC (System on a Chip) including an AXI (REGISTERED TRADEMARK) (Advanced eXtensible Interface) specification, for example, an exclusive control of a memory access in the SoC has been implemented so as to ensure a secure and software sequence of a common resource in an OS (Operating System).

Specifically, when executing one OS by using an SoC including a plurality of CPUs (Central Processing Units) or even when ensuring a common resource in different OSs, it may be required to implement an exclusive control beyond a chip (semiconductor integrated circuit). However, even when requiring an exclusive control beyond such a chip, a propagation function of the exclusive control may not previously provided between the chips applying to different bus specifications.

Here, the AXI (REGISTERED TRADEMARK) is included in an AMBA (REGISTERED TRADEMARK) (Advanced Microcontroller Bus Architecture), which is a general term for an on-chip interconnect specification, for example, together with an AHB (REGISTERED TRADEMARK) (Advanced High-performance Bus) and an APB (REGISTERED TRADEMARK) (Advanced Peripheral Bus). Further, for example, an OCP (Open Core Protocol), a PIF (Processor InterFace), etc., may be known as specifications other than the AMBA.

As described above, between chips including (applying to) different bus specifications, an exclusive control function may not previously provided. For example, a propagation function of an exclusive control has not been previously prepared between a semiconductor integrated circuit including a PCIe (REGISTERED TRADEMARK) (Peripheral Component Interconnect Express) specification which is widely used, and an SoC including an AXI specification.

Such no propagation function of the exclusive control is provided between semiconductor integrated circuits, circuit boards or the like including different bus specifications is the same as between semiconductor integrated circuits, circuit boards or the like to which various other bus specifications may be applied.

Here, the present invention is not limited to an exclusive control propagation between a PCIe specification and an AXI specification, but also applied to an exclusive control propagation between semiconductor integrated circuits, circuit boards or the like including different bus specifications. Specifically, the present invention may be possible to apply to an exclusive control propagation between a semiconductor integrated circuit or the like including a PCIe and a semiconductor integrated circuit or the like including an AMBA such as an AXI, an AHB and an APB or a semiconductor integrated circuit or the like including an OCP or a PIF.

Incidentally, in the prior art, for example, various techniques have been proposed for an exclusive control in a multiprocessor system.

Patent Document 1: Japanese Laid-open Patent Publication No. H06(1994)-110844

Patent Document 2: Japanese Laid-open Patent Publication No. H08(1996)-161228

SUMMARY

According to an aspect of the embodiments, there is provided a bus control circuit configured to transfer an exclusive command between a first bus specification and a second bus specification by mutually converting a first exclusive command including a first format and applying to the first bus specification which deals with an exclusive access, and a second exclusive command including a second format and applying to the second bus specification which is different from the first bus specification and does not deal with the exclusive access, includes an exclusive command conversion circuit, an exclusive command generation circuit, an exclusive response issuing circuit, and an exclusive response receiving circuit.

The exclusive command conversion circuit is configured to receive the first exclusive command, convert the first exclusive command into the second exclusive command and output the second exclusive command, when converting from the first exclusive command to the second exclusive command, and the exclusive command generation circuit is configured to receive the second exclusive command and generate the first exclusive command, when converting from the second exclusive command to the first exclusive command

The exclusive response issuing circuit configured to issue exclusive response information for the second exclusive command, when converting from the second exclusive command to the first exclusive command, and the exclusive response receiving circuit is configured to receive exclusive response information for the second exclusive command, when converting from the first exclusive command to the second exclusive command.

The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram depicting an example of an information processing device according to the present embodiment;

FIG. 2 is a block diagram depicting an example of a bus control circuit in a semiconductor integrated circuit in the information processing device depicted in FIG. 1;

FIG. 3 is a diagram for explaining an example of transmitting an exclusive command using a TLP header of a PCIe packet in the information processing device depicted in FIG. 1;

FIG. 4 is a diagram for explaining a basic configuration of an AXI (Part 1);

FIG. 5 is a diagram for explaining the basic configuration of the AXI (Part 2);

FIG. 6 is a diagram for explaining an example of signals in the AXI;

FIG. 7 is a diagram for explaining an example of an exclusive access in the AXI;

FIG. 8 is a diagram for explaining a response used in the AXI;

FIG. 9 is a diagram for explaining an operation of an exclusive access in the AXI;

FIG. 10 is a diagram for explaining an example of a read access operation in the information processing device depicted in FIG. 1;

FIG. 11 is a diagram for explaining an example of an exclusive read access operation in the information processing device depicted in FIG. 10;

FIG. 12 is a diagram for explaining an example of a write access operation in the information processing device depicted in FIG. 1;

FIG. 13 is a diagram for explaining an example of an exclusive write access operation in the information processing device depicted in FIG. 12;

FIG. 14 is a diagram for explaining another example of an exclusive read access operation in the information processing device depicted in FIG. 10 and FIG. 11;

FIG. 15 is a block diagram depicting another example of an information processing device according to the present embodiment;

FIG. 16 is a diagram for explaining an example of an exclusive command conversion block for a read channel in the bus control circuit depicted in FIG. 2;

FIG. 17 is a diagram for explaining an example of an exclusive command conversion block for a write channel in the bus control circuit depicted in FIG. 2;

FIG. 18 is a diagram for explaining an example of an exclusive response receiving block for a read channel in the bus control circuit depicted in FIG. 2;

FIG. 19 is a diagram for explaining an example of an exclusive command generation block for the read channel in the bus control circuit depicted in FIG. 2;

FIG. 20 is a diagram for explaining an example of an exclusive command generation block for the write channel in the bus control circuit depicted in FIG. 2;

FIG. 21 is a diagram for explaining an example of an exclusive response issuing block for the write channel in the bus control circuit depicted in FIG. 2;

FIG. 22 is a diagram for explaining a method of generating/restoring header information including ST bits [7:0] in the information processing device with reference to FIG. 1 and FIG. 2 (Part 1); and

FIG. 23 is a diagram for explaining the method of generating/restoring header information including ST bits [7:0] in the information processing device with reference to FIG. 1 and FIG. 2 (Part 2).

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of a bus control circuit, a semiconductor integrated circuit, a circuit board, an information processing device and a bus control method will be described in detail with reference to the accompanying drawings. FIG. 1 is a block diagram depicting an example of an information processing device according to the present embodiment. In FIG. 1, reference numeral 100 denotes an SoC (semiconductor integrated circuit), and 200 denotes a PCIe (REGISTERED TRADEMARK) bus.

In FIG. 1, two SoCs (SoC #0, SoC #1) 100 are connected by a PCIe bus (PCIe) 200 as an example, however, the number of SoCs 100 is not limited to two, and a specification of the SoC 100 is not limited to the AXI. Further, the bus connecting the plurality of SoCs 100 is not limited to the PCIe 200.

Note that, the SoC 100 is formed as a single semiconductor integrated circuit (chip), but the SoC 100 may also be formed as a plurality of chips. Furthermore, in FIG. 1, a circuit board 300 is formed by the SoC 100 (controller) and a memory 101, and an information processing device (for example, a server) is formed by a plurality of circuit boards 300, but the present embodiment may be widely applied to various configurations.

As depicted in FIG. 1, each circuit board 300 includes an SoC 100 and a memory (for example, DDR (Double-Data-Rate) Memory) 101. The circuit board 300 may include various chips (semiconductor integrated circuits). The SoC 100 includes a bus control circuit (exclusive access circuit) 1, a CPU 102, an internal connection circuit (Interconnect) 103, memory connection circuits (104, 105), external connection circuits (106, 107), and various IPs ((IP: Intellectual Property) cores, IP macros) 108.

The memory connection circuit includes, for example, a memory control circuit (DDR Controller) 104 for controlling a connection with a memory (DDR Memory) 101, and an interface IP macro (DDR PHY) 105 of the memory 101. The external connection circuit includes, for example, a link control circuit (PCIe Link) 106 for controlling a connection (link) with the other SoC 100 (circuit board 300) through a PCIe 200, and an interface IP macro (physical layer of PCIe: PCIe PHY) 107.

The internal connection circuit 103 exchanges signals (data and commands) between the CPU 102, and the memory control circuit (DDR Controller) 104, the bus control circuit 1 and the IP macros 108 based on the AXI specification. Further, the CPU 102, the memory control circuit 104, the IP macros 108 and the like may constitute an internal circuit of the AXI specification (internal bus specification). Here, the bus control circuit 1 receives and converts signals of the AXI specification, and outputs to the PCIe (external bus) 200 through the external connection circuit (link control circuit 106 and the physical layer 107). Further, the bus control circuit 1 converts signals input from the PCIe 200 through the external connection circuits (106, 107), and outputs to the internal connection circuit 103 (CPU 102, the memory control circuit 104 and the IP macros 108, etc.) of the AXI specification.

The bus control circuit 1 includes an exclusive command conversion block A-1, an exclusive response issuing block A-2, an exclusive command generation block B-1 and an exclusive response receiving block B-2, and is provided on each of the SoCs 100.

Here, when the exclusive command is output from one SoC #0 through the PCIe 200 to the other SoC #1 (when an exclusive access is issued from the SoC #0 to the SoC #1), blocks A-1, A-2, B-1 and B-2 in each of the SoCs 100 operate as follows. In one SoC #0, the blocks A-1 and B-2 are turned ON (activated), and the blocks A-2 and B-1 are turned OFF (inactivated); and in the other SoC #1, the blocks A-1 and B-2-are turned OFF, and the blocks A-2 and B-1 are turned ON.

Note that the exclusive access indicates an access, for example, in the case of sharing resources (memory, etc.) and wherein, while a specific portion (specific address of the memory, etc.) of the shared resources is accessed by the SoC #0, the specific portion the shared resources may not be accessed by the SoC #0 so as to maintain an integrity of the shared resources. Further, the exclusive command indicates a command for requesting the exclusive access, for example, including an exclusive read command and an exclusive write command.

On the other hand, a normal access indicates an access, for example, not including the above exclusive control. Further, a normal command indicates a command for requesting the normal access, for example, including a normal read command and a normal write command.

FIG. 2 is a block diagram depicting an example of a bus control circuit in a semiconductor integrated circuit in the information processing device depicted in FIG. 1. As depicted in FIG. 2, in each semiconductor integrated circuit (SoC #0, SoC #1) 100, a bus control circuit (PCIe Exclusive Access Unit) 1 includes a first converter (Interconnect to PCIe Bus Bridge) 11 for converting signals from an internal connection circuit 103 to external connection circuits 106, 107 connected to a PCIe 200. Further, the bus control circuit 1 includes a second converter (PCIe to Interconnect Bus Bridge) 12 for converting signals from the external connection circuits 106, 107 connected to the PCIe 200, to the internal connection circuit 103.

The first converter 11 receives and converts an exclusive command from the internal connection circuit 103, and outputs the converted command to the external connection circuits 106, 107 connected to the PCIe 200; and the first converter 11 includes a command conversion block A-1, an exclusive response issuing block A-2, and a selector 10.

Here, the command conversion block A-1 is a circuit, for example, which receives an exclusive command applying to an AXI specification and including a format suitable for an exclusive control within the semiconductor integrated circuit 100 from the internal connection circuit 103, converts into an exclusive command applying to an AXI specification and including another format suitable for the PCIe specification, and outputs to the external connection circuits 106, 107.

Further, the exclusive response issuing blocks A-2 is a circuit, for example, which receives exclusive response information included in the exclusive command applying to the AXI specification of the internal connection circuit 103 from an exclusive command generation block B-1, and issues the exclusive response information suitable for the PCIe specification to the external connection circuits 106, 107. Note that the selector 10 is a circuit for selecting an output of the command conversion block A-1 or the exclusive response issuing blocks A-2, and outputting to the PCIe 200.

The second converter 12 receives and converts the exclusive command from PCIe 200, and outputs the converted command to the internal connection circuit 103, and the second converter 12 includes the exclusive command generation block B-1 and the exclusive response receiving block B-2.

Here, the exclusive command generation block B-1 is a circuit, for example, which receives an exclusive command applying to an AXI specification and including a format suitable for the PCIe specification from the external connection circuits 106, 107 connected to the PCIe 200, generates an exclusive command applying to an AXI specification and including another format suitable for an exclusive control within the semiconductor integrated circuit 100, and outputs the generated command to the internal connection circuit 103. Further, the exclusive response receiving block B-2 is a circuit, for example, which receives exclusive response information for the exclusive command issued from the external connection circuits 106, 107 to the PCIe 200, and output the received command to the block A-1.

Next, an example using a PCIe (REGISTERED TRADEMARK) and an AXI (REGISTERED TRADEMARK) as different two bus specifications for converting an exclusive access in the present embodiment will be explained with reference to FIG. 3 to FIG. 9, and thereafter, the present embodiment will be explained in detail with reference to FIG. 10 to FIG. 23.

FIG. 3 is a diagram for explaining an example of transmitting an exclusive command using a TLP header of a PCIe packet in the information processing device depicted in FIG. 1, and for explaining the case of inputting Misc (misc (miscellaneous)) signals of the AXI. Here, the Misc signals are, for example, a user signal which may be defined by a user in the AXI, and used for propagating miscellaneous information. Note that FIG. 3 indicates a memory write request header in a TLP (Transaction Layer Packet) header of a PCIe packet, and a memory read and atomic operation request header.

As described with reference to FIG. 1, for example, when an exclusive access is issued from one SoC #0 to the other SoC #1, in the SoC #0, the blocks A-1 and B-2 are turned ON, and in the SoC #1, the blocks A-2 and B-1 are turned ON. Here, the TLP header in the PCIe includes a structure as depicted in FIG. 3, and performs a conversion of an exclusive access by using, for example, TH (TLP Processing Hint present) bits, which are open to the user, ST[7:0] fields and PH (Processing Hint) bits. Note that, in the present specification, for example, an example of using a TLP header as a bit field in the PCIe incorporating an exclusive command in the AXI will be explained, however, this is merely an example, and various types of bit fields in the PCIe specification may be used.

Specifically, in the SoC #0, TH bits of a TLP header in a PCIe, ST[7:0] fields and PH bits are treated as Misc signals of the AXI input to the PCIe. The external connection circuits 106, 107 of the SoC #0 generate TH bits of the TLP header, ST[7:0] fields, and PH bits in the PCIe based on bit information of the Misc signals of the AXI. The Misc signals may include, for example, ARUSER[x:0] and AWUSER[x:0] of the AXI, which will be described later.

Further, in the SoC #1, Misc signals of the AXI are treated as the TH bits of the TLP header in the PCIe, the ST[7:0] fields and the PH bits input to the AXI. PCIe, Here, the external connection circuits 106, 107 of the SoC #0 generate Misc signals of the AXI base on bit information of the TH bits of the TLP header in the PCIe, the ST[7:0] fields and the PH bits.

The Misc signals may include, for example, ARUSER[x:0] and AWUSER[x:0] of the AXI, which will be described later.

Note that bits treated as the Misc signals are not limited to TH bits of a TLP header in a PCIe, ST[7:0] fields and PH bits, but the Misc signals may use other bits which are open to the user. Furthermore, it is of course that bits used for converting the exclusive access is not limited to those in the TLP header.

FIG. 4 and FIG. 5 are diagrams for explaining the basic configuration of the AXI. As depicted in FIG. 4(a), an AXI includes a read address for reading (AR) channel “Read address channel” and a read data (R) channel “Read data channel”. Further, the AXI includes a write address for writing (AW) channel “Write address channel”, a write data (W) channel “Write data channel” and a write response (B) channel “Write response channel”. Therefore, the AXI includes five channels.

FIG. 4(b) is a diagram for explaining a read operation in the AXI and FIG. 4(c) is a diagram for explaining a write operation in the AXI. Note that, in FIG. 4(b) and FIG. 4(c), “AXI Master” is assumed to the CPU 102 of the SoC #0 depicted in FIG. 1, and “AXI Slave” is assumed to the memory (DDR memory) 101 of the SoC #1 depicted in FIG. 1.

Further, between the “AXI Master” and the “AXI Slave”, an internal connection circuit 103 of the SoC #0, a bus control circuit 1 and external connection circuits 106, 107, PCIe 200, external connection circuits 106, 107 of the SoC #1, and the like are provided.

As depicted in FIG. 4(b), when data from the “AXI Master” to the “AXI Slave” (memory 101 in the SoC #1) is read, “AR” and “R” depicted in FIG. 4(a) are used. Further, as depicted in FIG. 4(c), when data from the “AXI Master” is written to the “AXI Slave”, “AW”, “W” and “B” depicted in FIG. 4(a) are used.

As depicted in FIG. 5, each channel includes signals of valid (VALID)/ready (READY)/transmission information (Information) for an operation of a transaction, and information is exchanged by a handshake of VALID/READY. Here, a reference CLK denotes a clock.

First, a transmitting side asserts a VALID signal (T1 depicted in FIG. 5) indicating that information is valid, and a receiver side asserts a READY signal indicating that the receiving side may receive the valid information. For example, a handshaking may be established at a specific edge of the clock when the VALID and READY signals are both high level “H”. Note that the transmitting side holds the Information and the VALID signal to a timing T2 depicted in FIG. 5. In this way, an exchange of information may be completed.

FIG. 6 is a diagram for explaining an example of signals in the AXI. In this embodiment, for example, signals ARLOCK[1:0], ARUSER[x:0], RRESP[1:0], AWLOCK[1:0], AWUSER[x:0] and BRESP[1:0] which are surrounded by a thick frame in FIG. 6 may be used. Here, the ARLOCK[1:0] indicates an atomic access and is a signal (AXI3 (version 3 of the AXI) only) designating usual/exclusive/lock accesses, and the ARUSER[x:0] is a user signal, which may be defined by a user, and is one of the above-mentioned Misc signals. Further, RRESP[1:0] indicates a read response, and is a signal indicating a result status of the read transfer. Note that a reference [x 0] indicates an arbitrary bit width.

Further, the AWLOCK[1:0] indicates an atomic access and is a signal (AXI3 only) designating usually/exclusive/lock accesses, and the AWUSER[x:0] is a user signal, which may be defined by a user, and is one of the above-mentioned Misc signals. Further, the BRESP[1:0] indicates a write response, and is a signal indicating a result status of the write transfer.

FIG. 7 is a diagram for explaining an example of an exclusive access in the AXI. As depicted in FIG. 7(a), values “00”, “01”, “10” and “11” of a 2-bit signal AxLOCK[1:0] indicate “normal access”, “exclusive access”, “lock access” and “reserved”, respectively. Note that the AxLOCK[1:0] indicates both ARLOCK[0 1] and ARLOCK[1 0]. Further, a value “10” of the AxLOCK[1:0] is removed in an AXI4 (version 4 of the AXI).

FIG. 7(b) indicates a case where accesses of a master 0 (Master 0: for example, a CPU 102 of the SoC #0) and a slave 0 (Slave 0: for example, a memory 101 of the SoC #0) are competed. Note that the slave 1 (Slave 1) is, for example, the memory 101 of the SoC #1.

As depicted in FIG. 7(b), when accesses a specific address (of the memory 101 in the SoC #0) is competed by the master 0 and the slave 0, it is possible to realize by, for example, a semaphore type processing. Here, so as to realize an exclusive access, an exclusive access monitor may be required to provide for the slave 0 (memory 101 of the SoC #0). Further, the exclusive access monitor for the Slave depicted in FIG. 7(b), monitors an address for accessing an Slave 0, for example, during an exclusive access from a Master 0 to the Slave 0, a Master 1 may be possible to access another address of the Slave 0.

FIG. 8 is a diagram for explaining a response used in the AXI. As depicted in FIG. 8, for example, a response used in the AXI is four types “OKAY”, “EXOKAY”, “SLVERR” and “DECERR” which correspond to values “00”, “01”, “10” and “11” represented by a 2-bit RRESP[1:0] and BRESP[1:0].

Here, the “OKAY” indicates that a normal access is successful or an exclusive access is failure, the “EXOKAY” indicates that one of an exclusive read or an exclusive write is successful, and the “SLVERR” indicates a slave error which is a notification from the slave to the master. Further, the “DECERR” indicates a decoding error, or an destination address is not present in the slave, and is usually generated by an interconnect.

Specifically, in the case of a write (writing), a single response is returned for an entire burst, and in the case of a read (reading), a response is returned for each data transfer in the burst. Here, it may be required to be possible to return different responses for each data transfer, and to perform required number of transfer operations even if an error occurs during the transfer operations.

FIG. 9 is a diagram for explaining an operation of an exclusive access in the AXI. Here, in an operation of the exclusive access, a semaphore access (read-modify-write) is a basic.

As depicted in FIG. 9(a), when the master performs an exclusive read (ARLOCK[0:1]=“01”), the exclusive monitor stores an address and an ID, and the slave returns read data to the master by the “EXOKAY”. Note that the slave, which is not dealing with an exclusive access, returns the “OKAY” to the master so as to notify that the slave is not compatible with the exclusive access.

As depicted in FIG. 9(b), when the master performs a modifier (modify) of data, while the exclusive monitor monitors whether or not a semaphore area is rewritten by another master. Note that the exclusive monitor continues a monitoring operation until causing a write operation from another master (ID) or an exclusive read operation to another address.

As depicted in FIG. 9(c), when the master performs an exclusive write (AWLOCK[0:1]=“01”) to after updated data, while the exclusive monitor continuously monitors the same address, an exclusivity is guaranteed, a write operation is performed, and the “EXOKAY” is returned. Further, if the exclusive monitor does not monitor the address, since the exclusivity is not guaranteed, the write operation is not performed, and the “OKAY” is returned.

Incidentally, since an exclusive control function is not provided for the PCIe, for example, in a system (information processing device) connected to two SoC #0 and SoC #1 applying to the AXI, it is difficult to perform an appropriate exclusive control.

FIG. 10 is a diagram for explaining an example of a read access operation in the information processing device depicted in FIG. 1. FIG. 11 is a diagram for explaining an example of an exclusive read access operation in the information processing device depicted in FIG. 10, and for explaining a conversion of AXI commands in the exclusive read access operation.

In FIG. 10 and FIG. 11, a bus used to exchange commands and various information within the SoC #0 and SoC #1 is an AXI, which deals with an exclusive read access, and a bus used to exchange commands and various information between the SoC #0 and SoC #1 is a PCIe, which does not deal with the exclusive read access. Note that, in FIG. 11, “xxxx” indicates read data, “yy” indicates exclusive responses. Further, ARUSER[x:0] (for example, exclusive access=“1”) are used as Misc signals.

As depicted in FIG. 10 and FIG. 11, first, an exclusive read access (exclusive read command) is issued from a CPU 102 (CPU #0) of the SoC #0 (step S1), and an exclusive read command is stored in an exclusive command conversion block A-1 (step S2: AR ARLOCK=“01”). Next, exclusive read information is set to Misc signals of the AXI by the block A-1 (step S3: AR ARUSER=“1”). Further, a normal read command (with Misc signals) is issued from the block A-1 (step S4: AR ARLOCK=“00”, ARUSER=“1”), for example, to an external connection circuit (link control circuit 106 and the PCIe PHY 107: PCIe #0) in the SoC #0.

Further, a read command including exclusive control information in header information is issued from the PCIe #0 (external connection circuit of the SoC #0) to the PCIe #1 (external connection circuit of the SoC #1) (step S5), and a normal read command (with Misc signals) is issued from the PCIe #1 to an exclusive command generation block B-1 (step S6: AR ARLOCK=“00”, ARUSER=“1”). Further, the block B-1 holds the normal read command (with Misc signals) (step S7), and generates an exclusive read command from the exclusive read information of the Misc signals (step S8).

Next, an exclusive read command is issued from the block B-1 in a memory 101 of the SoC #1 (DDR #1) (step S9: AR ARLOCK=“01”), the DDR #1 issues an exclusive read response (step S10), and the exclusive read response is held by the block B-1 (step S11: R RDATA=“xxxx”, RRESP=“yy”).

Further, read data (Read Data) is output from the block B-1 to the PCIe #1 as a response of the normal read command (step S12: R RDATA=“xxxx”, RRESP=“00”), and identification information (exclusive read response information) for indicating an exclusive read response is issued from the block B-1 to the exclusive response issuing blocks A-2 based on the exclusive read response held by the block B-1 (step S13: R RRESP=“yy”). In addition, a normal write command where exclusive read response information is as write data (Write Data) is issued from the block A-2 to the PCIe #1, and the PCIe #1 receives the normal write command and issues a response indicating a successful of the normal write to the block A-2 (step S14: AW AWLOCK=“00”, W WDATA=“yy”, B BRESP=“00”).

Furthermore, read data (Read Data)/write data (Write Data) is transferred from the PCIe #1 to the PCIe #0 (step S15), and a read data transfer for the normal read command is performed from the PCIe #0 to the block A-1 (step S16: R RDATA=“xxxx”, RRESP=“00”). Further, a normal write command where exclusive read response information is as write data is issued from the PCIe #0 to the block B-2, and the block B-2 receives the normal write command and issues a response indicating a successful of the normal write to the PCIe #0 (step S17: AW AWLOCK=“00”, W WDATA=“yy”, B BRESP=“00”). In addition, the exclusive read response information is transferred from the block B-2 to the block A-1 (step S18: W WDATA=“yy”), the read data/exclusive read response information are merged by the block A-1, and an exclusive read response is transferred to the CPU #0 (step S19: R RDATA=“xxxx”, RRESP=“yy”).

As described above, for example, an exclusive read processing may be realized between two semiconductor integrated circuits (SoCs) applying to AXI specifications and each including an exclusive read function, connected by a PCIe which does not include an exclusive read function. Specifically, a propagation of an exclusive access may be possible between buses including different specifications.

FIG. 12 is a diagram for explaining an example of a write access operation in the information processing device depicted in FIG. 1. FIG. 13 is a diagram for explaining an example of an exclusive write access operation in the information processing device depicted in FIG. 12, and for explaining a conversion of an AXI command of an exclusive write access operation.

In FIG. 12 and FIG. 13, a bus used for exchanging commands or various information within an SoC #0 and an SoC #1 is an AXI dealing with an exclusive write access, and a bus used for exchanging commands or various information between the SoC #0 and SoC #1 is a PCIe not dealing with an exclusive write access. Note that, in FIG. 13, a reference “xx” indicates write data, “yy” indicates exclusive responses. Further, AWUSER[x:0] is used for Misc signals (for example, exclusive access=“1”).

As depicted in FIG. 12 and FIG. 13, first, an exclusive write access (exclusive write command) is issued from a CPU #0 (CPU 102 of the SoC #0) (step S21), and the exclusive write command is held in an exclusive command conversion block A-1 (step S22: AW AWLOCK=“01”, W WDATA=“xx”). Next, exclusive write information is set to Misc signals of an AXI by the block A-1 (step S23). Further, a normal write command (with Misc signals) is issued from the block A-1, for example, to a PCIe #0 (external connection circuits 106, 107 of the SoC #0) (step S24: AW AWLOCK=“00”, AWUSER=“1”, W WDATA=“xx”).

Furthermore, a write command including exclusive control information as header information from the PCIe #0 to the PCIe #1 (step S25), a the normal write command (with Misc signals) is issued from the PCIe #1 to an exclusive command generation block B-1, and the block B-1 receives the normal write command and issues a response indicating successful receipt (step S26: AW AWLOCK=“00”, AWUSER=“1”, W WDATA=“xx”, B BRESP=“00”). In addition, the normal write command (with Misc signals) is held and an exclusive write command is generated from exclusive write information of the Misc signals by the block B-1 (step S28).

Next, an exclusive write command is issued from the block B-1 to a DDR #1 (memory 101 of the SoC #1) (step S29: AW AWLOCK=“01”, W WDATA=“xx”), the DDR #1 issues an exclusive write response (step S30), and the exclusive write response is held by the block B-1 (step S31: B BRESP “yy”).

Further, identification information (exclusive write response information) for indicating an exclusive write response is issued from the block B-1 to an exclusive response issuing block A-2 based on the exclusive write response held by the block B-1 (step S32: B BRESP by “yy”).

In addition, a normal write command where exclusive write response information is as write data (Write Data) is issued from the block A-2 to the PCIe #1, and the PCIe #1 receives the normal write command and issues a response indicating a successful of the normal write to the block A-2 (step S33: AW AWLOCK=“00”, W WDATA=“yy”, B BRESP=“00”).

Furthermore, write data is transferred from the PCIe #1 to the PCIe #0 (step S34), a normal write command where exclusive write response information is as write data is issued from the PCIe #0 to an exclusive response receiving block B-2, and the block B-2 receives the normal write command and issues a response indicating a successful of the normal write to the PCIe #0 (step S35: AW AWLOCK=“00”, W WDATA=“yy”, B BRESP=“00”). In addition, the exclusive write response information is transferred from the block B-2 to the block A-1 (step S36), and the exclusive write response is transferred to the CPU #0 by the block A-1 (step S37: B BRESP=“yy”).

As described above, for example, an exclusive write processing may be realized between two semiconductor integrated circuits (SoCs) applying to AXI specifications and each including an exclusive write function, connected by a PCIe which does not include an exclusive write function. Specifically, a propagation of an exclusive access may be possible between buses including different specifications.

FIG. 14 is a diagram for explaining another example of an exclusive read access operation in the information processing device depicted in FIG. 10 and FIG. 11, and for explaining an example of performing an exclusive read access operation without using Misc signals of an AXI.

As is apparent from a comparison FIG. 14 with FIG. 11 described above, in a modified embodiment where an exclusive read access operation is performed without using Misc signals, steps S4′ and S6′ are additionally provided to the steps S1 to S19 depicted in FIG. 11.

Specifically, a step S4′ is performed in addition to the step S4 (AR ARLOCK=“00”, ARUSER=“1”) where a normal read is issued from the exclusive command conversion block A-1 to the PCIe. In the step S4′, exclusive read information is issued as a normal write command of the AXI from the block A-1 to the PCIe by, for example, AR ARLOCK=“00”, ARUSER=“1”. Further, the PCIe #0 receives the normal write command, and issues a response indicating successful receipt to the block A-1.

Further, a step S6′ is performed in addition to the step S6 (AR ARLOCK=“00”, ARUSER=“1”) where a normal read is issued from the PCIe #1 to an exclusive command generation block B-1. In the step S6′, exclusive read information is issued as a normal write command of the AXI from the PCIe #1 to the block B-1 by, for example, AW AWLOCK=“00”, W WDATA=“1”, and the block B-1 receives the normal write command, and issues a response indicating successful receipt to the PCIe #1.

Furthermore, the block B-1 generates an exclusive read command of the AXI based on the normal read command (step S6) and the normal write command of the exclusive read information (step S6′). Similarly, an exclusive write access operation may be possible to perform without using Misc signals. Therefore, it is possible to realize an exclusive access processing without using Misc signals of a PCIe.

FIG. 15 is a block diagram depicting another example of an information processing device according to the present embodiment, and depicting an example of an information processing device where three SoCs of AXI specifications (SoC #0, SoC #1, SoC #2) 100 are connected by a PCIe 200. Specifically, as is apparent from a comparison FIG. 15 with FIG. 1 described above, the information processing device depicted in FIG. 15 additionally includes an SoC #2 to the information processing device depicted in FIG. 1.

Here, a circuit board 300 including the SoC #2 and a memory 101, for example, corresponds to a motherboard, and two circuit boards 300 (SoC #0, SoC #1) are inserted to sockets of the mother board (SoC #2). Note that, in the SoC #0 to SoC #2, each of the SoCs (semiconductor integrated circuits) includes a number (SoC number) for identifying itself, or a port number (corresponding to a socket of the motherboard (SoC #2)) is assigned to each of the SoC #0 to SoC #2 so as to identify each circuit board 300 mounting the SoC 100.

Note that FIG. 15 depicts, for example, the case where the CPU 102 of the SoC #0 accesses the memory 101 connected to the SoC #1, and blocks A-1 and B-2 in a bus control circuit 1 of the SoC #0 are activated (ON). Further, two external connection circuits (106, 107) and the bus control circuit 1 are provided for the SoC #2, and in the case of accessing between the SoC #0 and SoC #1, the blocks A-1, A-2, B-1 and B-2 of the bus control circuit 1 are all inactivated (OFF). Furthermore, the number of SoCs 100 (circuit board 300) is not limited to two or three, and a larger number of SoCs (circuit board) of may be connected, as described above.

FIG. 16 is a diagram for explaining an example of an exclusive command conversion block for a read channel in the bus control circuit depicted in FIG. 2. As depicted in FIG. 16, the exclusive command conversion block A-1 includes a block A-11 for performing conversion processing of a read address (RA) channel and a block A-12 for performing conversion processing of read data (R) channel, at the time of a read access operation as described with reference to FIG. 10 and FIG. 11.

The block A-11 receives S_A1_ARLOCK and S_A1_ARADDR from the CPU #0 (internal connection circuit 103) by the step S1 depicted in FIG. 10 and FIG. 11, converts into D_A1_ARLOCK, D_A1_ARID[x] and D_A1_ARUSER[0], and outputs to the PCIe #0 (step S4). Note that, as described in detail, S_A1_ARLOCK and S_A1_ARADDR are used as D_A1_ARLOCK and D_A1_ARADDR.

Specifically, the block A-11 outputs D_A1_ARLOCK=“00” (normal access), D_A1_ARID[x]=“1” (for an exclusive command identification of R-channel, in addition to ARID[x-1:0] of x bits), and D_A1_ARUSER[0]=“1” (exclusive command information) to the PCIe #0, when S_A1_ARLOCK=“01” (exclusive access). Further, the block A-11 transfers the value of D_A1_ARADDR to the exclusive response receiving block B-2 as B2_AWADDR (for command identification), when S_A1_ARLOCK=“01”.

In addition, the block A-11 receives S_A1_ARLOCK and S_A1_ARADDR, converts into D_A1_ARLOCK=S_A1_ARLOCK, D_A1_ARID[x]=“0” and D_A1_ARUSER[0]=“0”, and outputs to the PCIe #0.

The block A-12 receives S_A1_RID[x] and S_A1_RRESP from the PCIe #0 by the step S16 depicted in FIG. 10 and FIG. 11, converts into D_A1_RRESP, and outputs to an internal connection circuit 103 (step S19). Specifically, the block A-12 outputs D_A1_RRESP=B2_RRESP (exclusive response value) to the CPU #0, when S_A1_RID[x]=is “1”. Further, the block A-12 outputs D_A1_RRESP=S_A1_RRESP to the CPU #0, when S_A1_RID[x]=“0”. Note that the block B-2 outputs B2_RRESP to the block A-12.

FIG. 17 is a diagram for explaining an example of an exclusive command conversion block for a write channel in the bus control circuit depicted in FIG. 2. As depicted in FIG. 17, the exclusive command conversion block A-1 includes a block A-13 for performing a conversion processing of a write address (AW) channel, a block A-14 for performing a conversion processing of write data (W) channel, and a block A-15 for performing a write response (B) channel, at the time of a write access operation as described with reference to FIG. 12 and FIG. 13.

The block A-13 receives S_A1_AWLOCK and S_A1_AWADDR from the CPU #0 by the step S16 depicted in FIG. 12 and FIG. 13, converts into D_A1_AWLOCK, D_A1_AWID[x] and D_A1_AWUSER, and outputs to a selector 10 (PCIe #0) (steps S22 to S24). Here, as described in detail below, S_A1_AWLOCK and S_A_AWADDR are used as D_A1_AWLOCK and D_A1_AWADDR.

Specifically, the block A-13 outputs D_A1_AWLOCK=“00” (normal access), D_A1_AWID[x]=“1” (for an exclusive command identification of B-channel, in addition to AWID[x-1:0] of x bits), and D_A1_AWUSER[0]=outputs “1” (exclusive command information) to the selector 10, when S_A1_AWLOCK=“01” (exclusive access). Further, the block A-13 transfers the value of D_A1_AWADDR to the exclusive response receiving block B-2 as B2_AWADDR (for command identification), when S_A1_AWLOCK=“01”.

In addition, the block A-13 receives S_A1_AWLOCK and S_A1_AWADDR, converts D_A1_AWLOCK=S_A1_AWLOCK, D_A1_AWID[x]=“0” and D_A1_AWUSER[0]=“0”, and outputs to a selector 10, when S_A1_AWLOCK=not “01”. Here, S_A1_AWLOCK indicating whether an exclusive access is determined to 2-bit data (“01”), however, it may be possible as one bit data (“0” or “1”).

The bock A-14 receives S_A1_AWLOCK from the CPU #0 by the step S21 depicted in FIG. 12 and FIG. 13, converts into D_A1_WID[x], and outputs to the selector 10 (PCIe #0) (step S22 to S24). Specifically, the block A-14 outputs D_A1_WID[x]=“1” (so as to match the AW channel), when S_A1_AWLOCK=“01” (exclusive access), and outputs D_A1_WID[x]=“0”, when S_A1_AWLOCK=not “01”. Note that the output of the block A-14 (D_A1_WID[x]) is input to the selector 10.

The block A-15 receives S_A1_BID[x] and S_A1_BRESP, converts into D_A1_BRESP, and outputs to the internal connecting circuit 103 (CPU #0) (step S37). Specifically, the block A-15 outputs D_A1_BRESP=B2_BRESP (exclusive response value) to the CPU #0, when S_A1_BID[x]=“1”, and outputs D_A1_BRESP=S_A1_BRESP to the CPU #0, when S_A1_BID[x]=“0”. Here, the exclusive response receiving block B-2 outputs B2_BRESP to the block A-15. Further, output signals of the exclusive response issuing block A-2 (outputs of AW, W and B channels) are also input to the selector 10, and the selector selects the output of the block A-2, for example, when receiving an exclusive response issuing identification signal (SS) which will be described later with reference to FIG. 21, and otherwise, selects the output of the block A-1.

FIG. 18 is a diagram for explaining an example of an exclusive response receiving block for a read channel in the bus control circuit depicted in FIG. 2. As depicted in FIG. 18, the exclusive response receiving block B-2 includes three blocks B-21, B-22 B-23 for performing a transfer processing and conversion processing between the exclusive command conversion block A-1 and the PCIe #0, at the time of an access operation as described with reference to FIG. 10 to FIG. 13.

The block B-21 receives B2_ARADDR and B2_AWADDR from the exclusive command conversion block A-1, also receives S_B2_AWADDR from an AW channel of the PCIe #0, and generates and outputs an exclusive response receiving identification signal (SR) to the block B-22. Specifically, in the block B-22, when S_B2_AWADDR is coincident with B2_ARADDR or B2_AWADDR, it is determined that the exclusive response is an exclusive command issued from the block A-1, and the block B-21 outputs an exclusive response receiving identification signal SR to the block B-22.

The block B-22 receives S_B2_WDATA from the PCIe #0 through a W channel, converts the S_B2_WDATA into B2_RRESP and B2_BRESP based on the exclusive response receiving identification signal SR from the block B-21, and outputs to the block A-1. Specifically, when a response is confirmed as an exclusive response for the exclusive command issued from the block A-1 based on the exclusive response receiving identification signal SR, the exclusive response value on S_B2_WDATA is transferred to the block A-1 as B2_RRESP or B2_BRESP. Note that the block B-23 is a block used to receive write response (B) channel information from the PCIe #0, however, the block B-23 is thin relationship with the present embodiment and descriptions thereof will be omitted.

FIG. 19 is a diagram for explaining an example of an exclusive command generation block for the read channel in the bus control circuit depicted in FIG. 2. As depicted in FIG. 19, the exclusive command generation block B-1 includes a block B-11 for performing a conversion processing of the an AR channel, and a block B-12 for performing a conversion processing of an R channel, at the time of a read access operation as described with reference to FIG. 10 and FIG. 11.

The block B-11 receives S_B_ARLOCK, S_B1_ARADDR and S_B1_ARUSER from the PCIe #1 as the step S6 depicted in FIG. 10 and FIG. 11, converts into D_B1_ARLOCK and D_B1_ARID[y], and outputs to the internal connection circuit 103 (DDR #1) (steps S7 to S10).

Specifically, the block B-11 outputs D_B1_ARLOCK=“01” (exclusive command), and D_B1_ARID[y]=“1” (for an exclusive command identification of R channel, in addition to ARID[y-1:0] of y bits) to the DDR #1, when S_B1_ARUSER[0]=“1” (exclusive command) Further, the block B-11 transfers the value of D_B1_ARADDR to the exclusive response issuing block A-2 as A2_ARADDR (for command identification), when S_B1_ARUSER=“1”. In addition, the block B-11 outputs D_B1_ARLOCK=S_B1_ARLOCK, and D_B1_ARID[y]=“0” to the DDR #1, when S_B1_ARUSER[0]=“0”.

The block B-12 receives S_B1_RRESP and S_B1_RID[y] as the step S11 depicted in FIG. 10 and FIG. 11, and converts into D_B1_RRESP, and outputs to the PCIe #1 (step S12). Specifically, the block B-12 outputs D_B1_RRESP=“00” and A2_RRESP=S_B1_RRESP (exclusive response value) to the PCIe #1, when S_B1_RID[y]=“1”. Further, the block B-12 outputs A2_RRESP to the block A-2.

FIG. 20 is a diagram for explaining an example of an exclusive command generation block for the write channel in the bus control circuit depicted in FIG. 2. As depicted in FIG. 20, the exclusive command generation block B-1 includes a block B-13 for performing a conversion processing of an AW channel, a block B-14 for performing a conversion processing of a W channel, and a block B-15 for performing a conversion processing of a B channel, at the time of a write access operation as described with reference to FIG. 12 and FIG. 13.

The block B-13 receives S_B1_AWLOCK, S_B1_AWADDR and S_B1_AWUSER[0] from the PCIe #1 by the step 26 depicted in FIG. 12 and FIG. 13, converts into D_B1_AWLOCK and D_B1_AWID[y], and outputs to the internal connection circuit 103 (DDR #1) (steps S27 to S30).

Specifically, the block B-13 outputs D_B1_AWLOCK=“01” (exclusive command), D_B1_AWID[y]=“1” (for an exclusive command identification of a B channel, in addition to AWID[y-1:0] of y bits), and a value of D_B1_AWADDR to the exclusive response issuing block A-2, when S_B1_AWUSER[0]=“1” (exclusive command). In addition, the block B-13 outputs D_B1_AWLOCK=S_B1_AWLOCK and D_B1_AWID[y]=“0” to the DDR #1, when S_B1_AWUSER[0]=“0”.

The block B-15 receives S_B1_BRESP and S_B1_BID[y], converts into D_B1_BRESP, and outputs to the PCIe #1. Specifically, the block B-15 outputs D_B1_BRESP=“00”, and A2_BRESP=S_B1_BRESP (exclusive response value) to the PCIe #1, when S_B1_BID[y]=“1”. Further, the block B-15 outputs A2_BRESP to the block A-2.

In addition, the block B-15 outputs D_B1_BRESP=S_B1_BRESP to the PCIe #1, when S_B1_BID[y]=“0”. Note that the block B-14 passes and outputs data of W channel from the PCIe #1 to the DDR #1.

FIG. 21 is a diagram for explaining an example of an exclusive response issuing block for the write channel in the bus control circuit depicted in FIG. 2. As depicted in FIG. 21, an exclusive response issuing blocks A-2 includes a block A-21 for performing a conversion processing of an AW channel, and a block A-23 for performing a conversion processing of a W channel, at the time of a write access operation as described with reference to FIG. 12 and FIG. 13.

The block A-21 receives B1_ARADDR and B1_AWADDR from the exclusive command generation block B-1 by the step S32 depicted in FIG. 12 and FIG. 13, converts into D_A2_AWADDR, and outputs to a selector 10 (PCIe #1) (step S13). Specifically, the block A-21 issues an AW command for an exclusive response to an AW channel (selector 10) by transferring B1_ARADDR or B1_AWADDR as D_A2_AWADDR, when receiving an exclusive response issuing identification signal SS from a block A-22 which will be described later.

The block A-22 receives B1_RRESP and B1_BRESP from the block B-1, converts into D_A2_WDATA, and outputs to a selector (PCIe #1). Specifically, the block A-22 transfers an exclusive response issuing identification signal SS to the AW channel and the selector 10 so as to issue an exclusive response, when the block A-22 receives B1_RRESP or B1_BRESP. Further, a value of B1_RRESP or B1_BRESP is converted as an exclusive value of D_A2_WDATA. Note that an explanation of the block A-23 is omitted, since the relationship is thin.

Here, as depicted in FIG. 21 and FIG. 17, the selector 10 is provided between the PCIe #1, and the exclusive command conversion block A-1 and the exclusive responses issuing blocks A-2, and signals selected by the selector 10 are transferred between the PCIe #1, and the block A-1 or A-2. Specifically, in the case of receiving an exclusive response issuing identification signal SS, the selector 10 selects a path A-2, and otherwise, the selector 10 selects a path A-1.

FIG. 22 and FIG. 23 are diagrams for explaining a method of generating/restoring header information including ST bits [7:0] in the information processing device with reference to FIG. 1 and FIG. 2, and for explaining an acquisition of information of SoC numbers or port numbers indicated with reference to FIG. 15. Note that, in FIG. 22 and FIG. 23, for example, a memory (DDR memory 101), memory connection circuits (104, 105), IP macros (108) and the like are omitted, since the relationship is thin.

As depicted in FIG. 22, an SoC 100 includes, for example, a flash memory controller 111, an electronic fuse (eFUSE) 112 and the set value register 113, in addition to the SoC described with reference to FIG. 1. Note that the flash memory controller 111 controls, for example, the flash memory (or, eEPROM) 114 provided outside of the 114 controls the flash memory controller 111.

The flash memory controller 111 includes an electronic fuse (eFUSE) 112 and a set value register 113. Note that the flash memory controller 111 controls, for example, a flash memory or a nonvolatile memory (Electrically Erasable Programmable Read-Only Memory: Flash/eEPROM: external memory) 114 provided outside of the flash memory controller 111.

The external memory (Flash/EEPROM) 114 or electronic fuse 112 stores previously SoC numbers or port numbers, for example, when power is turned ON, a CPU (or controller) 102 reads out values stored in the external memory 114 or the electronic fuse 112, and copies to a setting value register 113. Further, the values copied to the setting value register 113 are read out by the bus control circuit (exclusive access circuit) 1, and in a state where each of the SoCs is identified, an exclusive access processing described above is performed. Note that the CPU 102 may set the values read out from the external memory 114 or the electronic fuses 112 directly to the bus control circuit 1 without passing through the setting value register 113.

Concretely, as depicted in FIG. 23, ST bit (ST[7:0]) in the PCIe TLP header described with reference to FIG. 3 may be used. Specifically, the bus control circuit (PCIe Exclusive Access Unit) 1 reads out, for example, SoC numbers of the SoC #0 (SoC Number [5:0]) and port numbers from the setting value register 113. Further, AxLOCK[1:0] and AxADDR[31:0] are read out through the internal connection circuit (Interconnect) 103, for example, by performing the process described above, and AxUSER[7:0], AxUSER[10:8] and AxADDR[31 0] may be output to the PCIe #.

Here, data of the SoC #0 is converted (generated) as, for example, SoC Number [5:0]+Port Number +AxLOCK[1:0]→AxUSER[7:0]→ST[7:0], and converted to header information by performing conversions as AxLOCK[1:0]→AxUSER[10:8]→TH+PH[1:0]. As described above, AxLOCK is, for example, a two-bot signal such as AxLOCK[1:0], however, AxLOCK may be one-bit signal, for example, “01” indicates an exclusive access and “00” indicates a normal access. Further, AxUSER[10:8], which may transfer information of 3 bits, for example, in this case, one bit is fixed and other two bits may be used.

As described above, for example, information embedded in ST[7:0], TH and PH[1:0] of a TLP header in the PCIe is, for example, recovered in the SoC #1. Specifically, for example, TH +PH[1:0]→AxUSER[10:8]→AxLOCK[1:0], and also ST[7:0]→AxUSER[7:0]]→response for transmission source information holding to recover the information embedded in the TLP header in the PCIe. Therefore, in the SoC #1, AxUSER[7:0], AxUSER[10:8] and AxADDR[31:0] is input from the PCIe #1 to the bus control circuit 1, and AxLOCK[1:0] and AxADDR[31:0] are output from the bus control circuit to the 1 internal connection circuit 103.

Note that, in the SoC #1, a setting value register 113 may be also provided, and steps of a reverse direction (from SoC #1 to SoC #0) in the above descriptions may be possible to perform. Further, the use of ST[7:0], TH and PH[1:0] of the TLP header described above is only an example, and other bit fields of the header or appropriate bits fields in each bus specification may be also possible to use.

All examples and conditional language provided herein are intended for the pedagogical purposes of aiding the reader in understanding the invention and the concepts contributed by the inventor to further the art, and are not to be construed as limitations to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although one or more embodiments of the present invention have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention. 

What is claimed is:
 1. A bus control circuit configured to transfer an exclusive command between a first bus specification and a second bus specification by mutually converting a first exclusive command including a first format and applying to the first bus specification which deals with an exclusive access, and a second exclusive command including a second format and applying to the second bus specification which is different from the first bus specification and does not deal with the exclusive access, comprising: an exclusive command conversion circuit configured to receive the first exclusive command, convert the first exclusive command into the second exclusive command and output the second exclusive command, when converting from the first exclusive command to the second exclusive command; an exclusive command generation circuit configured to receive the second exclusive command and generate the first exclusive command, when converting from the second exclusive command to the first exclusive command; an exclusive response issuing circuit configured to issue exclusive response information for the second exclusive command, when converting from the second exclusive command to the first exclusive command; and an exclusive response receiving circuit configured to receive exclusive response information for the second exclusive command, when converting from the first exclusive command to the second exclusive command.
 2. The bus control circuit according to claim 1, wherein the first exclusive command is a command previously prepared based on the first bus specification, and the second exclusive command is generated based on a certain bit field in the second bus specification so as to perform the exclusive access.
 3. The bus control circuit according to claim 2, wherein the certain bit field in the second bus specification used for generating the second exclusive command is included in a header portion of a packet in the second bus specification.
 4. The bus control circuit according to claim 1, further comprising: a selector configured to control a selection between a path coupled to a second bus applying to the second bus specification, and a path according to the exclusive command conversion circuit or a path according to the exclusive command issuing circuit, based on an exclusive response issuing identification signal output from the exclusive response issuing circuit.
 5. The bus control circuit according to claim 1, wherein when converting from the first exclusive command to the second exclusive command, the exclusive response receive circuit is configured to issue exclusive command response information for the second exclusive command to the exclusive command conversion circuit, and the exclusive command conversion circuit is configured to generate an exclusive response for the first exclusive command based on the exclusive command response information for the second exclusive command
 6. The bus control circuit according to claim 5, wherein when converting from the first exclusive command to the second exclusive command, the exclusive command conversion circuit is configured to receive a response for a normal command, and generate an exclusive response for the first exclusive command, based on the response for the normal command and the exclusive command response information for the second exclusive command.
 7. The bus control circuit according to claim 1, wherein when converting from the second exclusive command to the first exclusive command, the exclusive command generation circuit is configured to receive an exclusive response for the first exclusive command, and issue an exclusive response information for the first exclusive command to the exclusive response issuing circuit, based on the exclusive response for the first exclusive command, and the exclusive response issuing circuit is configured to generate an exclusive response information for the second exclusive, based on the exclusive response information for the first exclusive command.
 8. The bus control circuit according to claim 7, wherein when converting from the second exclusive command to the first exclusive command, the exclusive command generation circuit is generate a response to a normal command, in addition to the exclusive response information for the first exclusive command, based on the exclusive response for the first exclusive command.
 9. A semiconductor integrated circuit comprising: a bus control circuit configured to transfer an exclusive command between a first bus specification and a second bus specification by mutually converting a first exclusive command including a first format and applying to the first bus specification which deals with an exclusive access, and a second exclusive command including a second format and applying to the second bus specification which is different from the first bus specification and does not deal with the exclusive access; an internal circuit applying to the first bus specification; an internal connection circuit configured to transfer signals between the bus control circuit and the internal circuit; and an external connection circuit configured to transfer signals between the bus control circuit and an external bus applying to the second bus specification, wherein the bus control circuit comprises: an exclusive command conversion circuit configured to receive the first exclusive command, convert the first exclusive command into the second exclusive command and output the second exclusive command, when converting from the first exclusive command to the second exclusive command; an exclusive command generation circuit configured to receive the second exclusive command and generate the first exclusive command, when converting from the second exclusive command to the first exclusive command; an exclusive response issuing circuit configured to issue exclusive response information for the second exclusive command, when converting from the second exclusive command to the first exclusive command; and an exclusive response receiving circuit configured to receive exclusive response information for the second exclusive command, when converting from the first exclusive command to the second exclusive command.
 10. The semiconductor integrated circuit according to claim 9, wherein the first exclusive command is a command previously prepared based on the first bus specification, and the second exclusive command is generated based on a certain bit field in the second bus specification so as to perform the exclusive access.
 11. The semiconductor integrated circuit according to claim 9, wherein when converting from the first exclusive command to the second exclusive command, the exclusive response receive circuit is configured to issue exclusive command response information for the second exclusive command to the exclusive command conversion circuit, and the exclusive command conversion circuit is configured to generate an exclusive response for the first exclusive command based on the exclusive command response information for the second exclusive command
 12. The semiconductor integrated circuit according to claim 11, wherein when converting from the first exclusive command to the second exclusive command, the exclusive command conversion circuit is configured to receive a response for a normal command, and generate an exclusive response for the first exclusive command, based on the response for the normal command and the exclusive command response information for the second exclusive command.
 13. The semiconductor integrated circuit according to claim 9, wherein when converting from the second exclusive command to the first exclusive command, the exclusive command generation circuit is configured to receive an exclusive response for the first exclusive command, and issue an exclusive response information for the first exclusive command to the exclusive response issuing circuit, based on the exclusive response for the first exclusive command, and the exclusive response issuing circuit is configured to generate an exclusive response information for the second exclusive, based on the exclusive response information for the first exclusive command.
 14. The semiconductor integrated circuit according to claim 13, wherein when converting from the second exclusive command to the first exclusive command, the exclusive command generation circuit is generate a response to a normal command, in addition to the exclusive response information for the first exclusive command, based on the exclusive response for the first exclusive command
 15. A circuit board comprising: the semiconductor integrated circuit according to claim 9; and a memory connected to at least the semiconductor integrated circuit, and shared by the semiconductor integrated circuit and a circuit different from the semiconductor integrated circuit.
 16. An information processing device including a plurality of the circuit boards according to claim 15, wherein each of the circuit boards is connected by a second bus applying to the second bus specification.
 17. A bus control method for transferring an exclusive command between a first bus specification and a second bus specification by mutually converting a first exclusive command including a first format and applying to the first bus specification which deals with an exclusive access, and a second exclusive command including a second format and applying to the second bus specification which is different from the first bus specification and does not deal with the exclusive access, comprising: receiving the first exclusive command, converting the first exclusive command, into the second exclusive command, and outputting the second exclusive command, when converting from the first exclusive command to the second exclusive command; receiving exclusive response information for the second exclusive command, when converting from the first exclusive command to the second exclusive command; receiving the second exclusive command and generating the first exclusive command, when converting from the second exclusive command to the first exclusive command; and issuing exclusive response information in response to the second exclusive command, when converting from the second exclusive command to the first exclusive command 